Ryanoids and related compounds — Chemoselective electrocatalytic hydrogenation of alkyl α-pyrrole carboxylates: Selective hydrogenation of ryanodine

2002 ◽  
Vol 80 (12) ◽  
pp. 1662-1667 ◽  
Author(s):  
Luc Ruest ◽  
Hugues Ménard ◽  
Vincent Moreau ◽  
François Laplante
Keyword(s):  
Amino Acid ◽  
Selective Hydrogenation ◽  
Pyrrole Ring ◽  
Biologically Active ◽  
Natural Amino Acid ◽  
Electrocatalytic Hydrogenation ◽  
Biological Interest ◽  
Catalytic Processes ◽  
Related Compounds

A study of the electrocatalytic hydrogenation (ECH) process of pyrrole and different alkyl pyrrole-2-carboxylates is presented. Once hydrogenated, the alkyl pyrrole-2-carboxylate becomes an ester of proline, an important natural amino acid. The process is chemoselective to the pyrrole ring. Ryanodine is a natural ryanoid known to be biologically active. The tetrahydroryanodine derivative thus obtained may now represent a molecule of high biological interest. The hydrogenation of ryanodine is possible with electrocatalytic and catalytic processes. In both cases the reaction is not diastereoselective.Key words: electrocatalytic hydrogenation, proline esters, ryanodine, tetrahydroryanodine.

Stability Constants of Some Metal Complexes Formed by Mimosine and Related Compounds

1979 ◽  
Vol 32 (1) ◽  
pp. 21 ◽  
Author(s):  
H Stunzi ◽  
DD Perrin ◽  
T Teitei ◽  
RLN Harris
Keyword(s):  
Amino Acid ◽  
Stability Constants ◽  
Metal Binding ◽  
Acid Group ◽  
Biologically Active ◽  
Amino Acid Group ◽  
Dimeric Complexes ◽  
Major Species ◽  
Active Amino Acid ◽  
Related Compounds

Complex formation of the biologically active amino acid L-mimosine [α-amino-β-(3-hydroxy-4-oxo-1,4-dihydropyridin-1-yl)propanoic acid (1)], mimosinic acid (2), mimosine methyl ether (9) and 3-hydroxy-1-methylpyridin-4(1H)-one (4) with Cu2+, Zn2+, Cd2+ and Pb2+ was studied. Stability constants were determined by potentiometric titration in 0.15M KNOB3 as inert electrolyte at 37�. In the monomeric complexes formed by the mimosine derivatives, metal binding by the hydroxypyridone moiety was favoured relative to the amino acid group. With mimosine, dimeric complexes were major species. Under physiological conditions, mimosine binds copper and zinc ions more strongly than do simpler amino acids.

Predicting the Strength of Stacking Interactions Between Heterocycles and Aromatic Amino Acid Side Chains

2019 ◽  
Author(s):  
Andrea N. Bootsma ◽  
Analise C. Doney ◽  
Steven Wheeler
Keyword(s):  
Amino Acid ◽  
Binding Sites ◽  
Aromatic Amino Acid ◽  
Aromatic Amino Acids ◽  
Biologically Active ◽  
Side Chains ◽  
Stacking Interactions ◽  
Inhibitor Binding ◽  
Protein Binding Sites ◽  
Amino Acid Side Chains

<p>Despite the ubiquity of stacking interactions between heterocycles and aromatic amino acids in biological systems, our ability to predict their strength, even qualitatively, is limited. Based on rigorous <i>ab initio</i> data, we have devised a simple predictive model of the strength of stacking interactions between heterocycles commonly found in biologically active molecules and the amino acid side chains Phe, Tyr, and Trp. This model provides rapid predictions of the stacking ability of a given heterocycle based on readily-computed heterocycle descriptors. We show that the values of these descriptors, and therefore the strength of stacking interactions with aromatic amino acid side chains, follow simple predictable trends and can be modulated by changing the number and distribution of heteroatoms within the heterocycle. This provides a simple conceptual model for understanding stacking interactions in protein binding sites and optimizing inhibitor binding in drug design.</p>

Analogues of the cholecystokinin octapeptide modified in the central part of the molecule

1991 ◽  
Vol 56 (9) ◽  
pp. 1963-1970 ◽  
Author(s):  
Jan Hlaváček ◽  
Václav Čeřovský ◽  
Jana Pírková ◽  
Pavel Majer ◽  
Lenka Maletínská ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Point Of View ◽  
Biologically Active ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Cholecystokinin Octapeptide ◽  
Biological Tests ◽  
Biological Potency ◽  
Biologically Active Conformation

In a series of analogues of the cholecystokinin octapeptide (CCK-8) the amino acid residues were gradually modified by substituting Gly by Pro in position 4, Trp by His in position 5, Met by Cle in position 6, or the Gly residue was inserted between Tyr and Met in positions 2 and 3 of the peptide chain, and in the case of the cholecystokinin heptapeptide (CCK-7) the Met residues were substituted by Nle or Aib. These peptides were investigated from the point of view of their biological potency in the peripheral and central region. From the results of the biological tests it follows that the modifications carried out in these analogues and in their Nα-Boc derivatives mean a suppression of the investigated biological activities by 2-3 orders of magnitude (at a maximum dose of the tested substance of 2 . 10-2 mg per animal).This means that a disturbance of the assumed biologically active conformation of CCK-8, connected with a considerable decrease of the biological potency of the molecule, takes place not only after introduction of the side chain into its centre (substitution of Gly4), but also after the modification of the side chains of the amino acids or by extension of the backbone in further positions around this central amino acid.

Synthesis of a Biologically Active Nonadecapeptide Corresponding to the First Nineteen Amino Acid Residues of Adrenocorticotropins1a

1961 ◽  
Vol 83 (21) ◽  
pp. 4449-4457 ◽  
Author(s):  
Choh Hao Li ◽  
Johannes Meienhofer ◽  
Eugen Schnabel ◽  
David Chung ◽  
Tung-Bin Lo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biologically Active ◽  
Amino Acid Residues

scholarly journals Beneficial Impacts of Incorporating the Non-Natural Amino Acid Azulenyl-Alanine into the Trp-Rich Antimicrobial Peptide buCATHL4B

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 421
Author(s):  
Areetha R. D’Souza ◽  
Matthew R. Necelis ◽  
Alona Kulesha ◽  
Gregory A. Caputo ◽  
Olga V. Makhlynets
Keyword(s):  
Amino Acid ◽  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Mechanism Of Action ◽  
Bactericidal Activity ◽  
Antimicrobial Agents ◽  
Human Cells ◽  
Side Chains ◽  
Natural Amino Acid ◽  
Proteolytic Stability

Antimicrobial peptides (AMPs) present a promising scaffold for the development of potent antimicrobial agents. Substitution of tryptophan by non-natural amino acid Azulenyl-Alanine (AzAla) would allow studying the mechanism of action of AMPs by using unique properties of this amino acid, such as ability to be excited separately from tryptophan in a multi-Trp AMPs and environmental insensitivity. In this work, we investigate the effect of Trp→AzAla substitution in antimicrobial peptide buCATHL4B (contains three Trp side chains). We found that antimicrobial and bactericidal activity of the original peptide was preserved, while cytocompatibility with human cells and proteolytic stability was improved. We envision that AzAla will find applications as a tool for studies of the mechanism of action of AMPs. In addition, incorporation of this non-natural amino acid into AMP sequences could enhance their application properties.

scholarly journals Chemical composition and antioxidant potential of Acacia leucophloea Roxb

2013 ◽  
Vol 72 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Muhammad Zia-Ul-Haq ◽  
Sanja Ćavar ◽  
Mughal Qayum ◽  
Inamullah Khan ◽  
Shakeel Ahmad
Keyword(s):  
Amino Acid ◽  
Chemical Composition ◽  
Amino Acid Profile ◽  
Major Fatty Acid ◽  
Biologically Active ◽  
Antioxidant Potential ◽  
Limited Information ◽  
Methanolic Extracts ◽  
Antioxidant Agent ◽  
Acacia Leucophloea

Abstract The aim of this study was to evaluate the compositional and nutritional potential of methanolic extracts of various parts of Acacia leucophloea Roxb. concerning the chemical composition and antioxidant potential of which limited information is available. Compositional studies indicated carbohydrates as major components in both seed and pods. Despite differences in mineral content among the leaves, pods and seeds, calcium was found in the highest amount and zinc in the lowest. The amino acid profile indicated aspartic acid as the major amino acid and proline as the minor. Among protein fractions, globulin was present in higher amounts than other fractions. Linoleic acid was the major fatty acid detected in the oil from both pods and seeds, while g-tocopherol was the major component of the tocopherol observed from same oil. Moreover, significant antioxidant potential was observed from the extracts of all three parts investigated. The results obtained in this study clearly indicate that A. leucophloea has a sufficient potential for use as a natural antioxidant agent. Further phytochemical studies will be performed for specification of the biologically active principles.

scholarly journals Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities.

1988 ◽  
Vol 8 (3) ◽  
pp. 1247-1252 ◽  
Author(s):  
E Lazar ◽  
S Watanabe ◽  
S Dalton ◽  
M B Sporn
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Amino Acid ◽  
Growth Factor ◽  
Aspartic Acid ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Single Amino Acid ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.

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